In multicast and broadcast applications, data are transmitted from a server to multiple receivers over wired and/or wireless networks. A multicast system as used herein is a system in which a server transmits the same data to multiple receivers simultaneously, where the receivers form a subset of all the receivers up to and including all of the receivers. A broadcast system is a system in which a server transmits the same data to all of the receivers simultaneously. That is, a multicast system by definition can include a broadcast system.
A station can be any wireless device including but not limited to a computer, a laptop, a notebook computer, a personal digital assistant (PDA), a dual mode smart phone, user device, a client device, a mobile terminal and a mobile device. A station can be transmitter, a receiver or a transceiver. Data communicated between devices can be text, audio, video or multimedia or any other kind of data. Data is usually formatted into packets and or frames. That is, frames and packets are formats into which the data is packaged for transmission convenience.
In the past several years, there has been a rapid growth of wireless network deployment in school campuses, shopping malls, hotels, airports, apartment buildings, and in homes. Emerging technology such as IEEE 802.11n radios make delivering multimedia contents over wireless networks possible. This increased deployment drives the technology deeper into our daily lives. Since the number of available wireless channels is limited, these channels have to be used or shared by multiple access points (APs) or base stations (BSs). In a dense deployment environment, for example in a multi-dwelling unit deployment with many APs in an apartment building or hotel, APs tend to interfere with each other. This impacts the throughput of wireless networks including the quality of service for multimedia streaming applications.
In the prior art, it has been proposed that each WLAN access point (AP) advertise the WLAN traffic load and the total traffic load that it estimates in the directly overlapping APs/WLANs in order to help other APs select operating channels and sharing of the operating channels. The total shared traffic load information advertised (provided) by an AP is the sum of the allocated traffic of this AP/WLAN, plus the value of the allocated traffic load of the overlapping APs/WLANs. The overlapping APs/WLANs are the APs/WLANs that can “hear” and interfere each other. For example, in FIG. 1, AP1 will advertise the traffic load of WLAN1 in its beacon or other management (control) signal (frames, packets). If AP1 shares the same channel and can hear the beacons from AP2, AP3, and AP4, AP1 will also advertise the sum of the traffic load of AP1/WLAN1, AP2/WLAN2, AP3/WLAN3, and AP4/WLAN4 in the total shared traffic load field. If AP1 can only hear the beacons from AP2/WLAN2 and AP3/WLAN3, not AP4/WLAN4, the total traffic load field advertised by AP1 is the sum of the traffic load of AP1/WLAN1, AP2/WLAN2, and AP3/WLAN3. However the total traffic load information advertised by an AP in its beacon or other management (control) signals (frames, packets) causes ambiguity. For example in FIG. 1, when AP2 receives the total traffic load information from AP1, AP2 does not know whether the total traffic load value from AP1 includes the traffic load of AP4/WLAN4 or not because AP2 does not know whether AP1 can hear AP4/WLAN4 and considered and included the AP4's/WLAN4's traffic load information in AP1's estimation of the total traffic load. Therefore, AP2 cannot make an optimal channel selection decision or a decision to share the channel with AP1.